Wednesday, June 21, 2017

Explaining Matter-Antimatter Asymmetry

I've long been an advocate of an approach to explaining the matter-antimatter asymmetry of the universe in which antimatter predominantly in a partner universe whose boundary with our own is at a shared Big Bang. A brief new paper explores the idea more formally, although the use of multiverse terminology is somewhat unfortunate for a proposal that lacks many of the flaws more commonly found in multiverse arguments.
In the multiverse, the universes can be created in entangled pairs with spacetimes that are both expanding in terms of the time variables experienced by internal observers in their particle physics experiments. The time variables of the two universes are related by an antipodal-like symmetry that might explain why there is no antimatter in our universe: at the origin, antimatter is created, by definition and for any observer, in the observer's partner universe. The Euclidean region of the spacetime that separates the two universes acts as a quantum barrier that prevents matter-antimatter from collapse.
Salvador J. Robles-Perez, "Restoration of matter-antimatter symmetry in the multiverse" (June 20, 2017).

An earlier version of the proposal from 2013 can be found here.

Why Are Hyaenas Smart?

Behavioural data indicate that there has been considerable convergence between primates and hyaenas with respect to their social cognitive abilities.
From here (hat tip to Razib Khan).

I have long attributed the exceptional intelligence of hyaenas, one of the most intelligent and successful African megafauna, to the fact that unlike most other mammals, the reproductive organs of hyaenas require both the male and female to be simultaneous aroused to reproduce. This has the effect of giving female hyaenas much more control of their reproductive decisions than comparable felines and canines. 

Hyaenas are the poster children for Planned Parenthood of the animal world.

Cosmopolitan Scandinavians Of Old And Y1K

In the Middle Ages in Europe it is commonly said that most people never traveled more than thirty miles from where they were born. But, then there were the Vikings:
In the centuries around and before 1000 A.D. there was a “Viking international” of sorts. Harald Hardrada may have died in England trying to become king of that nation, but he served for a time in the Varangian Guards in Constantinople. His connections to Kievan Rus were such that priests in the Eastern Christian tradition were brought in to aid in the conversion of Norway.
N.B. The time period that I call Y1K was a fascinating one all over the world. For example, Viking Lief Erikson makes it to the New World, the Gypsies start their migration from India, the Brahui migrate from the Deccan Peninsula to the Indus River Valley, the Crusades start one of the first very distant foreign wars in history, and more.

Even before the Vikings, the Bronze Age Scandinavians got around as well. There is evidence of trade of amber for Egyptian jewelry that brought goods, and probably people with them, from the Baltic Sea to Egypt.

Monday, June 19, 2017

Physics Is Culturally Neutral

Lubos Motl should know better than to make the ad hominem argument that a physics concept is discredited just because a Nobel Prize winning physicist who also became a Nazi at some point in his life toyed with the idea.

In this case he is attacking the loop quantum gravity approach to quantum gravity (he prefers the approach to quantum gravity based upon gravitons in 10-11 dimensional string theory), because the physicist who invented the cathode ray tube (which was at the heart of all video screens for half a century) toyed with a somewhat similar aether theory.

Loop quantum gravity (LQG) is a really a class of theories of quantum gravity that argues that, as in general relativity, gravity involves a background independent deformation of space-time, rather than a force mediated by a boson in the special relativistic space-time background of quantum-mechanics. Thus, in loop quantum gravity, there is quantization of space-time at the Planck scale, rather than quantization of a force acting between particles.

It is certainly fair game to criticize potential flaws in one of the two major approaches to quantum gravity, which is one of the great unsolved problems of physics, and eventually he does address some of his concerns on that score.

But, it is not fair game to field as an argument against LQG the politics of an admittedly technically accomplished physicist who explored a distant predecessor of the idea, any more than it is to denounce half a century of television screens as "Nazi Science". This is the kind of criticism that confuses people who don't know better while not informing or persuading anyone who does know better. It is particularly unseemly coming from someone whose own distasteful politics and poor social skills appear to have cost him a position in the physics department at Harvard, despite his clearly solid command of the discipline of physics itself, however, opinionated he might be in that regard towards rival approaches in his discipline.

Motl's offhand accusations of plagiarism directed at an academic rival (which having read many of the academic rival's papers, I can confidently tell you is hog wash), and his failure to engage in the real issues by offering up straw man versions of LQG, are likewise unworthy of a serious and sincere academic.

Wednesday, June 14, 2017

Social v. Solo Spider Genetics

Social spiders have a homogenized, less diverse gene pool than solo spiders.

Chesapeake Bay Conceals A 35 Million Year Old Impact Crater

There is a 35 million year old impact crater from an extraterrestrial impact in Chesapeake Bay (which is in the vicinity of Washington D.C.). 

This particular impact isn't associated with any major extinction event extreme enough to find in the paleological record, although it surely had lesser climate and impact effects, but it is a good illustration of how a body of water can conceal an impact crater.

Parsi Genetics

I have seen the new paper on the genetics of the contemporary Parsi (i.e. Zoroastrian) population of South Asia, but I didn't blog it, except in passing as a link to a post that mentions it in another post. Here is the abstract and citation to the paper (emphasis mine).
The Parsis are one of the smallest religious communities in the world. To understand the population structure and demographic history of this group in detail, we analyzed Indian and Pakistani Parsi populations using high-resolution genetic variation data on autosomal and uniparental loci (Y-chromosomal and mitochondrial DNA). Additionally, we also assayed mitochondrial DNA polymorphisms among ancient Parsi DNA samples excavated from Sanjan, in present day Gujarat, the place of their original settlement in India. 
Among present-day populations, the Parsis are genetically closest to Iranian and the Caucasus populations rather than their South Asian neighbors. They also share the highest number of haplotypes with present-day Iranians and we estimate that the admixture of the Parsis with Indian populations occurred ~1,200 years ago. Enriched homozygosity in the Parsi reflects their recent isolation and inbreeding. We also observed 48% South-Asian-specific mitochondrial lineages among the ancient samples, which might have resulted from the assimilation of local females during the initial settlement. Finally, we show that Parsis are genetically closer to Neolithic Iranians than to modern Iranians, who have witnessed a more recent wave of admixture from the Near East. 
Our results are consistent with the historically-recorded migration of the Parsi populations to South Asia in the 7th century and in agreement with their assimilation into the Indian sub-continent's population and cultural milieu "like sugar in milk". Moreover, in a wider context our results support a major demographic transition in West Asia due to the Islamic conquest.
Gyaneshwer Chaubey, et al., "'Like sugar in milk': reconstructing the genetic history of the Parsi population"(June 14, 2017)

Tuesday, June 13, 2017

Baryon Effects Can't Save Cold Dark Matter Models

The New Result

Simulations that include only Cold Dark Matter (CDM) don't reproduce something close to reality at the galaxy scale. One argument that this doesn't invalidate CDM models is that interactions between ordinary matter and dark matter (baryon effects) cure this problem and bring CDM models more closely into line with observed reality. CDM models can include baryon effects that can solve the problem, but they have to be highly unrealistic to accomplish this goal.

Now, a realistic, bottom up effort to determine that magnitude of these baryon effects has established that baryon effects don't solve the problems with cold dark matter models that are revealed in simulations using only cold dark matter.

Where Does This Leave Us?

First, dark matter phenomena are absolutely real and everyone agrees that this is the case. But, there is lack a consensus explanation of the mechanism behind these phenomena.

Warm Dark Matter Is Still Viable, But Is Tightly Constrained

This new result leaves basically one viable particle dark matter model: warm dark matter (WDM) with particles with masses of ca. 2-15 keV. There are very tight constraints on the parameter space of WDM, but those constraints still, just barely, leave a narrow mass range open. If one were looking for a theoretical framework to fit WDM into, a gravitino without other SUSY particles, a right handed neutrino, or a sterile neutrino singlet would both be plausible, yet minimal models. But, a neutrino that oscillates with ordinary neutrinos is also extremely constrained in parameter space.

Some Gravity Modification Theories Are Still Viable

There are also multiple gravity modification theories that could explain dark matter phenomena, although some gravity modification theories have been shown to be inconsistent with experiment. (Not, however, due to the Bullet Cluster which actually favors modified gravity theories over particle dark matter theories.)

Self-Interacting Dark Matter Models Are Pretty Much Ruled Out

Models with a 5th force finite but long range Yukawa force transmitted by a massive boson that acts between dark matter particles called self-interacting dark matter (SIDM) looked promising for a while. But, pretty much all plausible models of SIDM have been completely ruled out because sufficiently strong self-interactions should give rise to dark matter annihilations which are not observed. Also, while Occam's razor is pretty neutral between the WDM and gravity modification approaches discussed above, it disfavors SIDM which basically requires both.

Axion Dark Matter Isn't Definitively Ruled Out But Is Materially Constrained

It isn't entirely clear how axion dark matter models measure up - the range of axion dark matter models under consideration is great and the phenomenology seems to be all over the map, and this approach isn't subject to the limitations associated with thermal dark matter models. Most axion dark matter proposals mostly aren't a good fit to the originally proposed particle that would explain why there is no CP violation in the strong force (which I have never found compelling), however. And, this parameter space is still meaningfully constrained.

Not Clear Where Wave Dark Matter Stands

Another proposal which I haven't seen definitively ruled out is wave dark matter.

Cold Dark Matter, Including WIMPs And MACHOs Are Ruled Out

But, pretty much the entire universe of CDM (the subset of CDM called WIMPs is already pretty much ruled out by direct detection experiments which is bad news for SUSY theories which generically predict WIMP dark matter candidates) and MACHOs (such as primordial black holes) has been ruled out in an increasingly convincing way.

Any Dark Matter Candidate Must Be Basically Sterile And Stable At Low Energies

Of course, by hypothesis, any particle that interacts via the electromagnetic force or strong force was ruled out. And, experiments in the parameter range that remains viable for any kind of dark matter particle rules out any weak force interactions comparable to those of the existing Standard Model particles. So, any dark matter candidate needs to be basically completely "sterile" (i.e. without interactions other than Fermi contact interactions), at least at low energies.

Dark matter must also be either completely stable, or "metastable" with a mean lifetime on the order of the age of the universe or more.

Two Waves Of Steppe Migration?

Davidski at his Eurogenes blog, buried in a lot of technical jargon and software discussion, makes a pretty notable observation

He observes that the steppe component of the autosomal genetics of some South Asian populations shows a greater affinity to ancient Yamnaya genomes, which he attributes to an earlier Indo-Aryan wave of migration (speaking an early dialect of Sanskrit), while the steppe component of some linguistically Indo-Iranian populations (the oldest attested ancestral versions of which are Avestan a.k.a. Zend, and Old Persian) shows greater affinity to ancient Andronovo genomes, which he attributes to a later Indo-Iranian wave of migration.

Some quotes from his post (quotation updated in this post on June 14, 2017 as indicated, all emphasis mine):
My main model is also a decent statistical fit for at least a number Indian groups, like, for instance one of the Gujarati subpopulations labeled GujaratiD in the Human Origins dataset. But it fails marginally for Pathans, so it's not a robust solution for all of South Asia. Incredibly, using Andronovo instead of Yamnaya in the Pathan model makes it work. Tajiks can also be modeled in this way using Andronovo. I say incredibly, because Pathans and Tajiks are obviously Iranic speakers, and their Iranic ancestors in all likelihood arrived in South Asia from the Eurasian steppe much later than the Indo-Aryan ancestors of the Kalash and most Indians. . . .
So what we might be seeing here is substructure within the steppe-related admixture amongst South Asians, with Indo-Aryan speakers apparently showing Yamnaya-related (Catacomb?) ancestry, and Iranic speakers, as well as possibly groups with significant Iranic ancestry, showing a preference for later Andronovo-related ancestry.
Update 14/06/2017: I've now had the chance to test many more Indo-Aryan and Iranic groups with my model. Most of these groups show a slight, non-significant, preference for Yamnaya_Samara as the steppe reference population. However, those that show a slight, and again non-significant, preference for Andronovo are usually Iranic, such as the Balochi in the graphs below. I'm not claiming that this proves anything, but I do think that it hints at something, and I'll try testing a few different hypothesis in the near future[.] 
In fairness to Davidski, should this not pan out, he has made clear that this analysis is preliminary and involves some of the first times that he has used a new software tool that he is not yet fully familiar with using. Also, as an editorial note, if I recall correctly, the GujaratiD population consists of ethnically Gujarati immigrants from India in Dallas, Texas. (Similarly, one of the major reference sets of Chinese genomes, CHD, consists of Han Chinese immigrants from Denver and one of the major reference sets for Northern European CEU, consists of white people from Utah).

This is very plausible in historical context. It would also explain why it is hard to develop a good fitting model that involves just a single wave of steppe migration to South and West Asia, which has been pretty much the default assumption so far.

ANI v. ASI Puzzles That May Or May Not Be Related

It isn't clear if this has anything to do with an analysis of contemporary South Asian genomes using linkage disequilibrium dating (a methodology that is heavily biased towards the most recent date of any admixture) that appears to reveal that places in North India, which should have encountered Indo-Aryans first, shows the youngest data of most recent Ancestral North Indian (ANI) admixture, suggesting that these areas experienced two, rather than one, wave of ANI admixture. But, it is quite possible that this is unrelated and that the ANI in both waves of admixture was basically the same genetic population.

I should also note that while ASI (Ancestral South Indian) genetics are probably autochthonous and from a single source, the ANI is a component is probably composed of multiple layers: a Paleolithic North Indian layer with a clinal relationship to ASI (possible pre-dating the Last Glacial Maximum ca. 18,000 BCE given its affinity of ASI to Onge DNA), a Harappan layer from West Asian Neolithic migrants (ca. 7000 BCE given the date of the Indus River Valley Neolithic), but possibly including additional migration, for example, in connection with an Uruk expansion from Mesopotamia that occurs around the time that Harappan civilization with which it had trade ties, emerges, and at least one subsequent layer of Indo-Aryan steppe migrant contributions (ca. 2000 BCE to 1500 BCE), but quite possibly two layers.

Uruk Expansion

Razib Khan has been dropping hints in several posts that he is interested in the explanatory possibilities of the Uruk expansion from Mesopotamia ca. 3600 BCE, that could be an important genetic and cultural source for the people in the nearby highlands of Anatolia, the Caucasus and West Asia, and ultimately perhaps also cultures influenced secondarily by those cultures such as the Minoans and maybe even the Yamnaya people.

I agree and think that this could be at the root, which is perhaps too deep in time depth to be discerned definitively from linguistic data given the quality of the available linguistic data, of the ergative languages of this region and perhaps also Basque.

About Kashmiri

Another interesting aside, from a post at the Brown Pundists blog, is that the Kashmiri language is closer in many respects to Sanskrit than other Indo-Aryan languages.

Wednesday, June 7, 2017

300,000 Year Old Modern Human Bones Found In Morocco

Image from here.

Just two days after a paper analyzing 2000 year old Khoi-San DNA from South Africa and determining that the Khoi-San divergence date from other African populations was ca. 260,000 years ago, there is an announcement that an anatomically modern human bone that is 300,000 years old has been found, much older than the oldest accurately dated modern human remains previously known from about 195,000 years ago in Ethiopia.
The oldest fossil remains of Homo sapiens, dating back to 300,000 years, have been found at a site in Jebel Irhoud, Morocco. This is 100,000 years older than previously discovered fossils of Homo sapiens that have been securely dated. The discovery was presented in a study in the journal Nature on Wednesday. 
This marks the first discovery of such fossils in north Africa, and widens the "cradle of mankind" to encompass all of Africa, the researchers said. Previous finds were in south or east Africa. The fossils, including a partial skull and a lower jaw, belong to five different individuals including three young adults, an adolescent and a child estimated to be 8 years old. Stone tools, animal bones and evidence of fire were also found within the same layer at the site.
This result doesn't strongly contradict the current paradigm, but does clearly push it in the direction of older anatomically modern human speciation (Y-DNA had pointed to a date about 270,000 years ago), and a wider geographic range within Africa of early modern humans. This also brings the speciation date closer to the divergence date for other archaic hominins like Neanderthals and Denisovans.

The abstract and citation to the paper are as follows:
The timing and location of the emergence of our species and of associated behavioural changes are crucial for our understanding of human evolution. The earliest fossil attributed to a modern form of Homo sapiens comes from eastern Africa and is approximately 195 thousand years old1, 2, therefore the emergence of modern human biology is commonly placed at around 200 thousand years ago3, 4. The earliest Middle Stone Age assemblages come from eastern and southern Africa but date much earlier5, 6, 7. Here we report the ages, determined by thermoluminescence dating, of fire-heated flint artefacts obtained from new excavations at the Middle Stone Age site of Jebel Irhoud, Morocco, which are directly associated with newly discovered remains of H. sapiens8. A weighted average age places these Middle Stone Age artefacts and fossils at 315 ± 34 thousand years ago. Support is obtained through the recalculated uranium series with electron spin resonance date of 286 ± 32 thousand years ago for a tooth from the Irhoud 3 hominin mandible. These ages are also consistent with the faunal and microfaunal9 assemblages and almost double the previous age estimates for the lower part of the deposits10, 11. The north African site of Jebel Irhoud contains one of the earliest directly dated Middle Stone Age assemblages, and its associated human remains are the oldest reported for H. sapiens. The emergence of our species and of the Middle Stone Age appear to be close in time, and these data suggest a larger scale, potentially pan-African, origin for both.
Daniel Richter, et al., "The age of the hominin fossils from Jebel Irhoud, Morocco, and the origins of the Middle Stone Age" 546 Nature 293–296 (June 7, 2017).

A sister paper discusses the taxonomy of these remains and assigns them to the "early stages of the H. sapiens clade" despite a mosaic and archaic and primitive features. It may be more fair to classify these remains as transitional between archaic and anatomically modern human, rather than a completely anatomically modern human individual. John Hawks is tweeting his skepticism about the classification of these remains as Homo sapiens with a cogent and fuller explanation here.
Fossil evidence points to an African origin of Homo sapiens from a group called either H. heidelbergensis or H. rhodesiensis. However, the exact place and time of emergence of H. sapiens remain obscure because the fossil record is scarce and the chronological age of many key specimens remains uncertain. In particular, it is unclear whether the present day ‘modern’ morphology rapidly emerged approximately 200 thousand years ago (ka) among earlier representatives of H. sapiens1 or evolved gradually over the last 400 thousand years2. Here we report newly discovered human fossils from Jebel Irhoud, Morocco, and interpret the affinities of the hominins from this site with other archaic and recent human groups. We identified a mosaic of features including facial, mandibular and dental morphology that aligns the Jebel Irhoud material with early or recent anatomically modern humans and more primitive neurocranial and endocranial morphology. In combination with an age of 315 ± 34 thousand years (as determined by thermoluminescence dating)3, this evidence makes Jebel Irhoud the oldest and richest African Middle Stone Age hominin site that documents early stages of the H. sapiens clade in which key features of modern morphology were established. Furthermore, it shows that the evolutionary processes behind the emergence of H. sapiens involved the whole African continent.
Jean-Jacques Hublin, et al., "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" 546 Nature289–292 (June 7, 2017)

SUSY With Different Assumptions

As the early efforts to use the GAMBIT software that fits data to supersymmetry (SUSY) and supergravity (SUGRA) models illustrates, the targets of these beyond the Standard Model (BSM) SUSY and SUGRA models are anything but random. Some of the assumptions include the following:

* Dark matter has a particle nature and is composed primarily of the lightest stable supersymmetric particle (the LSP). Usually, this is accomplished with conservation of a supersymmetric quantum number called R-parity, although sometimes R-parity conservation is only approximate allowing for an unstable LSP with a lifetime on the order of the lifetime of the universe.

* Neutrinos are Majorana particles. Often a see-saw model and right handed neutrinos are assumed as well.

* None of the Standard Model particles are super-partners of each other.

* SUSY and SUGRA models are embedded in a larger grand unified theory (GUT) that gives rise to gauge coupling unification at a GUT scale.

* The extended boson sector of SUSY And SUGRA do not create any new fundamental forces with new fields that have additional coupling constants, and certainly not to any with phenomenological importance that is observed empirically.

* The gluons, the photon and the graviton are the only zero mass particles.

I'm sure that there are other  important assumptions that I've overlooked.

Suppose that you remove the assumption that there is a stable or metastable LSP because dark matter phenomena can be fully understood as arising from graviton self-interactions (as proposed, for example, by Alexandre Deur) not properly accounted for in general relativity, rather than from dark matter particles. This would make R-parity conservation unnecessary (and indeed, maybe even preferable to do without to avoid creating additional kinds of dark matter which have not been detected experimentally). The lack of the need for an LSP also reduces pressure on the need for an LSP that is fairly close to the electroweak scale in mass.

Also, suppose that supersymmetric particles exist at high energy scales far in excess of the electroweak scale, for example, with masses on the order of 1-50+ TeV, as LHC results to date strongly suggest, although relaxing the assumption that there is a stable or metastable LSP also greatly opens up the parameter space of supersymmetry. This masses might be tied not to the ordinary Higgs boson (which would be the light scalar little h Higgs boson in this scenario), but to a heavy quartet of Higgs bosons (A, H, H+ and H-) at masses of the same order of magnitude as the mass scale of the heaviest supersymmetric particles.

Naively, this would lead us to expect that it is highly likely that supersymmetric particles would have very short lifetimes, presumably far shorter  than those of the top quark, Higgs boson, W boson and Z boson which are currently the most short lived known particles (although how a particle could experience W boson weak decay in a time period of less than the W boson lifetime is problematic, perhaps a W' boson would be necessary). 

Of course, while this would make fitting experimental data easier, it isn't obvious that this achieves much in terms of explanatory power. Certainly, for example, it does little to solve the hierarchy problem in a "natural" way which was a major motivator for SUSY in the first place.

Monday, June 5, 2017

One Guy's Ideas About Links Between The Harappan And Brahmi Script

The paper is Subhajit Ganguly, "Relation Between Harappan And Brahmi Scripts" (copyright 2012 uploaded in 2017).

It is posted on the vixra site (an ungated pre-print archive mostly for non-professional researchers) which is notorious for crackpot postings, particularly in some of its forums such as those related to fundamental physics, but is not always so far off the mark in some of its other forums. Nothing on the vixra site, including this paper, should be taken as proven, but every once and a while one of its authors produce some interesting ideas like this one that deserve a little further attention. There are several other papers posted at the site by the same author on the same theme.

The abstract states:
Around 45 odd signs out of the total number of Harappan signs found make up almost 100 percent of the inscriptions, in some form or other, as said earlier. Out of these 45 signs, around 40 are readily distinguishable. These form an almost exclusive and unique set. The primary signs are seen to have many variants, as in Brahmi. Many of these provide us with quite a vivid picture of their evolution, depending upon the factors of time, place and usefulness. Even minor adjustments in such signs, depending upon these factors, are noteworthy. Many of the signs in this list are the same as or are very similar to the corresponding Brahmi signs. These are similarities that simply cannot arise from mere chance. It is also to be noted that the most frequently used signs in the Brahmi look so similar to the most frequent Harappan symbols. The Harappan script transformed naturally into the Brahmi, depending upon the factors channelizing evolution of scripts.
The Harappan script is last attested ca. 1900 BCE when that civilization collapsed and remains undeciphered with disputed theories regarding its origins and the origins of the language it describes. There are credible claims, however, that it continued to be used on a limited basis until 1500 BCE or even as late as 1100 BCE. There is serious dispute over whether the Harappan script codes a true language, or merely a proto-language made up mostly of trademarks, analogous to the Vinca script of the Neolithic Vinca culture in the Balkans. Per Wikipedia
An opposing hypothesis that has been offered by Michael Witzel and Steve Farmer, is that these [Harappan] symbols are nonlinguistic signs which symbolise families, clans, gods, and religious concepts—similar to components of coats of arms or totem poles. In a 2004 article, Farmer, Sproat, and Witzel presented a number of arguments stating that the Indus script is nonlinguistic, principal among them being the extreme brevity of the inscriptions, the existence of too many rare signs (increasing over the 700-year period of the Mature Harappan civilization), and the lack of the random-looking sign repetition typical of language.
A couple of credible academic claims have been made, however, that the script actually codes the Harappan language.

The earliest attested version of the Brahmi script is roughly the 3rd century BCE and its origins are disputed among professionals, and it wouldn't take many undiscovered inscriptions to bridge the gap in an area where there is probably a significant amount remaining to be discovered in the archaeological record. The leading view is that the Brahmi script is ultimately derived from the Phoenician script that is the source of the Roman and Greek alphabets, for example, but this is not a consensus view and the argument for an indigenous origin of the script also has credible supporters within academic linguistics.

Tuesday, May 30, 2017

GAMBIT Is Incomplete But Furthers SUSY Falsification

The community of supersymmetry (SUSY) phenomenologists and kindred beyond the Standard Model (BSM) theorists has come up with a software package called GAMBIT that analyzes the available parameter space of particular beyond the standard model theories, such as various versions of SUSY and another grand unified theories (GUTs) on a global basis in light of the available data.

This makes sense because any given fit of data to a BSM theory is an arduous task, but most of the very sophisticated and difficult parts of the analysis can be generalized to any member of a large class of BSM theories. 

For example, every analysis must appropriately reflect the uncertainties in the values of the measured experimental constants used as model inputs and appropriately weigh the impact of those uncertainties on the likelihood that a place of the parameter space of the BSM model is not ruled out by experiment.

The First Three GAMBIT papers

So far, GAMBIT has been fed real data and produced results reported in three inaugural pre-prints.

* One looks at scalar singlet dark matter models. In this paper (emphasis mine):
We include the dark matter relic density measured by Planck, direct searches with LUX, PandaX, SuperCDMS and XENON100, limits on invisible Higgs decays from the Large Hadron Collider, searches for high-energy neutrinos from dark matter annihilation in the Sun with IceCube, and searches for gamma rays from annihilation in dwarf galaxies with the Fermi-LAT. Viable solutions remain at couplings of order unity, for singlet masses between the Higgs mass and about 300 GeV, and at masses above ∼1 TeV. Only in the latter case can the scalar singlet constitute all of dark matter. Frequentist analysis shows that the low-mass resonance region, where the singlet is about half the mass of the Higgs, can also account for all of dark matter, and remains viable. However, Bayesian considerations show this region to be rather fine-tuned.
This result, in fact, is far too optimistic because it doesn't include a complete set of constraints.

There is simulation based data related to dark matter halo shapes that disfavor models with two significant kinds of dark matter like those in the 125 GeV to 300 GeV mass range, and there is experimental data related to dark matter halo shape and galaxy dynamics that strongly disfavors masses above 1 TeV (or for that matter masses in the range of 125 GeV to 300 GeV, or around 62.5 GeV).

As noted in the SUSY GUT paper below at page 8, in an observation that is true for all GAMBIT parameter fits:
The likelihood that we employ penalises only models that predict more than the observed relic density.
So, models that produce insufficient dark matter are still treated as viable, contrary to the data from dark matter research. This would be a serious problem were it not for the fact that the MSSM and most similar models generically produces too much, and not too little dark matter.

Also, the only reason that direct dark matter detection experiments have not more definitively ruled out dark matter particles heavier than 1 TeV is because the experiments were designed to be sensitive to lighter dark matter particles which were considered far more likely to exist. There is no affirmative experimental data favoring very heavy cold dark matter particles like these, just a lack of precision tests that are sensitive to a mass range thoroughly disfavored by astronomy data, which are also not well motivated by the considerations that led scientists in the 1980s to come up with SUSY theories in the first place.

paper summing up the results of a June 2012 dark matter conference reached conclusions that have still not been credibly rebutted, which SUSY theorists simply choose to ignore rather than address on the merits:
Evidence that Cold Dark Matter (ΛCDM), CDM+ baryons and its proposed tailored cures do not work in galaxies is staggering, and the CDM wimps (DM particles heavier than 1 GeV) are strongly disfavoured combining theory with galaxy astronomical observations. 
One also needs to accept extremely low cross-sections of interaction with ordinary matter for any these models to be viable due to the LUX data, which are not consistent with naive formulations of SUSY theories that should have cross-sections of interaction of a magnitude comparable to at least the cross-sections of interaction associated with the weak force interactions of ordinary neutrinos, without any plausible theoretical motivation for this in a SUSY framework. As Jester explained in his most recent blog post:
If the WIMP were true to its name, that is to say if it was interacting via the weak force (meaning, coupled to Z with order 1 strength), it would have order 10 fb scattering cross section on neutrons. Unfortunately, that natural possibility was excluded in the previous century. Years of experimental progress have shown that the WIMPs, if they exist, must be interacting super-weakly with matter. For example, for a 100 GeV fermionic dark matter with the vector coupling g to the Z boson, the current limits imply g ≲ 10^-4.
In other words, any interaction between a massive WIMP and ordinary matter is 10,000 times weaker than the weak force that applies to all other Standard Model particles.

Cold dark matter that has thermal relic particles of 1 GeV or more that is not "self-interacting" via a dark matter only 5th force, and is not completely inert with respect to ordinary matter, is pretty much completely ruled out by the astronomy data. And honestly, self-interacting dark matter models are also in serious trouble. Yet, all of the theories analyzed by GAMBIT to date includes dark matter particles of this type.

* One looks at a version of the Minimal Supersymmetric Standard Model called MSSM7 (because it has 7 free parameters).

One non-obvious conclusion of this analysis is that the MSSM generically produces far too much thermal relic dark matter unless one of five specific forms of annihilation of dark matter with other dark matter exists to reduce the amount of dark matter in the universe today. These are:

- chargino co-annihilation;
- stop co-annihilation;
- sbottom co-annihilation;
- A/H funnel; and
- h/Z funnel

The best fit results cluster around just a couple of those five specific forms of dark matter annihilation, although the parameter values for the MSSM7 parameters favored aren't heavily dependent upon the dark matter annihilation mechanisms incorporated in the theory. Specifically, the A/H funnel and sbottom co-annihilation scenarios are closer to the best fit values than that h/Z funnel, and chargino co-annihilation and stop co-annihilation diverge the furtherest from best fits that are not limited to these dark matter annihilation models.

It also bears noting that there is not a shred of credible positive experimental evidence for any of the particles involved in any of the three annihilation modes or the A/H funnel. All of those theories are purely "god of the gaps" material whose viability hinges on a lack of sufficient experimental evidence to rule them out for all possible parameter values. Experiments have not fully ruled them out at all masses and in all variations, but they have seen no data to support their existence. Only the h/Z funnel primarily involves particles that are known to really exist and it isn't particular favored by the analysis.

Another point to note is that the case for the MSSM7 hinges heavily on three data points, all of which should be viewed with suspicion. One involved the properties of the Higgs boson has measured at the LHC, which do not yet perfectly square with the Standard Model expectation even though they are converging towards that prediction as more data accumulates. The second involves gamma rays observed with the Fermi-LAT satellite which most observers attribute to astronomy sources in a poorly known background rather than BSM physics. The third and most dominant at this point are the anomalous, lepton universality violations observed in certain B meson decays that have been disappearing as Run-2 data becomes available.

In general, the fits of the data to the MSSM7 tend to favor a light neutralino (ca. 200 GeV), and a very heavy CP-Odd Higgs boson (more than 5 TeV).

Like the scalar singlet dark matter model study above, this analysis fails to consider the rather compelling data from dark matter halo shapes and galaxy dynamics that strongly disfavor the heavy dark matter candidates proposed.

* One looks at SUSY GUTs. The abstract of this paper is as follows (emphasis added):
We present the most comprehensive global fits to date of three supersymmetric models motivated by grand unification: the Constrained Minimal Supersymmetric Standard Model (CMSSM), and its Non-Universal Higgs Mass generalisations NUHM1 and NUHM2. We include likelihoods from a number of direct and indirect dark matter searches, a large collection of electroweak precision and flavour observables, direct searches for supersymmetry at LEP and Runs I and II of the LHC, and constraints from Higgs observables. Our analysis improves on existing results not only in terms of the number of included observables, but also in the level of detail with which we treat them, our sampling techniques for scanning the parameter space, and our treatment of nuisance parameters. We show that stau co-annihilation is now ruled out in the CMSSM at more than 95% confidence. Stop co-annihilation turns out to be one of the most promising mechanisms for achieving an appropriate relic density of dark matter in all three models, whilst avoiding all other constraints. We find high-likelihood regions of parameter space featuring light stops and charginos, making them potentially detectable in the near future at the LHC. We also show that tonne-scale direct detection will play a largely complementary role, probing large parts of the remaining viable parameter space, including essentially all models with multi-TeV neutralinos.
As in the MSSM7 paper, the existence of one of a handful of particular dark matter annihilation methods is critical to making these models viable, because otherwise these SUSY GUT models generically predict the existence of too much dark matter.

And, like all of the other papers, the GAMBIT model ignores the fact that heavy cold dark matter is strongly disfavored by the astronomy data. See, for example, page 4 of the SUSY GUT paper which notes in describing GAMIT's dark matter model that:
Because we do not employ any observables in our fits that depend on the Milky Way density profile, the spatial part of this [dark matter] model plays no role.

Despite all sorts of little corners of the SUSY and GUT parameter space that are not ruled out by GAMBIT, all of these fits hinge heavily on some anomalous early results with limited data that are already starting to go away at the LHC, and all of these dark matter models are made possible only by ignoring important data points from astronomy that strongly disfavor heavy, thermal relic, cold dark matter which all of these models assume.

In truth, the kind of simple SUSY formulations proposed in these models have not been ruled out already only because an army of institutionally committed SUSY theorists are performing CPR upon them with all of their might despite the fact that these patients are already dead - a point that is pretty clear to anyone looking at the forest rather than only at the trees.

GAMBIT considers all sorts of constraints and a mutual and interacting basis, but, it ignores key constraints from astronomy that strongly disfavor cold dark matter of 10 GeV or more based upon issues like halo shape, because including this constraint would annihilate all of the models the software is designed to analyze rendering the whole effort futile at the get go. So, this community has chosen to engage the data only selectively in order to preserve its sacred cows.

This doesn't mean that GAMBIT is useless. It still greatly narrows the part of parameter space that has to be considered by someone seeking to rule out SUSY, so that defeat of these models in detail is, at least in principle, theoretically possible by taking its output and then adding additional constraints that GAMBIT ignores.

GAMBIT also does a relatively good job of demonstrating, by example, that a lot of the key problems with the current batch of SUSY theories are generic over a wide range of SUSY theory variations.

The take home message of this latest round of efforts to confront SUSY with the experimental data is that the assumptions that need to be made to keep SUSY alive are now far outside the parameter space ranges that motivated SUSY in the first place, that essentially all simple SUSY theories in existence are ruled out by adding the full set of constraints to those analyzed by GAMBIT, and that seekers of a BSM theory that works (because we still need, at a minimum, a viable quantum gravity theory and a better explanation of the barrage of Standard Model constants) would be well advised to consider SUSY a dead end and look elsewhere.

Moreover, since SUSY is the low energy approximation of most interesting versions of String Theory, String Theory is also on the endangered list as a viable explanation of our real physical universe, even if it produces cool and sometimes even useful mathematical concepts and tools.

The Earliest Domesticated Rice In China

The earliest domesticated rice in China dates to 7400 BCE at Shangshan near the Yangtze River. This is about 400 years older than the oldest known domesticated rice as of June 2016 in the same general vicinity.

Image from here.

The paper and its abstract are as follows:
Phytolith remains of rice (Oryza sativa L.) recovered through the Shangshan site from the Lower Yangtze of China have previously been recognized as the earliest examples of rice cultivation. However, because of the poor preservation of macroplant fossils, many radiocarbon dates were derived through undifferentiated organic materials in pottery sherds. These materials remain a source of debate because of potential contamination by old carbon. Direct dating of the rice remains might serve to clarify their age. Here, we first validate the reliability of phytolith dating from the study region through a comparison with dates obtained through various other material through the same layer or context. Our phytolith data indicate which rice remains retrieved through early stages of the Shangshan in addition to also also Hehuashan sites have ages of approximately 9,400 in addition to also also 9,000 calibrated years before the present, respectively. The morphology of rice bulliform phytoliths indicates they are closer to modern domesticated species than to wild species, suggesting which rice domestication may have begun at Shangshan during the beginning of the Holocene.
“Dating rice remains through phytolith carbon-14 study reveals domestication at the beginning of the Holocene,” Proceedings of the National Academy of Sciences (2017).


This is close in time the earliest cultivation of millet, probably ca. 7700 BCE in Inner Mongolia. An millet took several hundred years after that to become a primary means of subsistence in North China, which may have happened as late as 5000 BCE. So, this find significantly narrows the gap in time between the North Chinese Neolithic and the South Chinese Neolithic, in which the North Chinese Neolithic had previously been believed to be significantly earlier.

The soybeans we associate with so many Asian and vegan foods (e.g. tofu, soy sauce, soy milk, edamame, tempeh) were domesticated much later, ca. 3500 BCE in Central China.

Wild rice was consumed by hunter-gatherers in India not long after it was domesticated in China, but the oldest evidence of domesticated rice in India is from 2000 BCE to 1800 BCE, about 5400-5600 years later. There is dispute over whether this involved one or more independent domestication events, or involved a domesticated strain derived at least in part from the earlier domesticated East Asian strain. Indian rice is domesticated very close in time to the arrival of East Asian rice, however, which probably arrived with the ancestors of the Munda people via Southeast Asia.

There was also an exchange of Sahel African and South Asian crops between South India and Northeast Africa or Yemen in the time period ca. 2500 BCE to 2000 BCE, that probably did not involve the Harappan civilization.

The domestication of sorghum has its origins in Ethiopia and surrounding countries, commencing around 4000 BCE –3000 BCE. Pearl millet (a Sahel African origin crop) was domesticated ca. 3200 BCE to 2700 BCE in West and/or Central Africa.

This is also quite close in time to the earliest domesticated crop cultivation in the Fertile Crescent. The earliest evidence for domesticated wheat, for example, is from 7050 BCE. Some other domesticated crops that became part of the Fertile Crescent Neolithic package came later. Most of the crops in Europe, Central and West Asia, northern India and North Africa were first domesticated in the Fertile Crescent with a few other domesticated in the Balkans.

Corn was domesticated between 6000 BCE and 8000 BCE in the Western Mexico. See also here. Pumpkins, squashes and gourds were also domesticated not long after 8000 BCE, possibly in Northern Mexico, although some subtypes of these crops were domesticated later. Turkeys were also probably domesticated in Mexico although the oldest available dates (ca. 500 CE) are probably doubtful as the oldest date of domestication, which is probably much older. Crops domesticated in the New World, other than the kumara squash, were post-Columbian exports to the rest of the world, and the kumara made its way to the Austronesians only about five hundred years before Columbus.

Papuans also began to domesticate crops at about the same time, but unlike other Neolithic cultures did not abandon hunting and foraging to rely primarily on farming and herding. Their crops did not make their way to the outside world until the modern era.

The simultaneous independent domestication of crops at multiple locations around the world was probably driven by a dramatic reduction in global climate volatility around that time.

Monday, May 29, 2017

Sunday, May 21, 2017

Do Yamnaya Autosomal Genetics Derive From Caucasian Mail Order Brides?

Davidski at Eurogenes proposes a model for the formation of the Yamnaya genotype that makes a couple of key assumptions set forth below (emphasis in the original): 
- It's likely that low population densities in Eastern Europe during the Eneolithic ensured the rapid spread and rise of admixture from the Caucasus across much of the Pontic-Caspian steppe, which then plateaued at around 50% during the Yamnaya period, when population densities on the steppe may have become high enough so that continued gene flow from the Caucasus no longer had much of an impact. 
- The process that led to the Yamnaya genotype eventually led to its extinction by the Late Bronze Age, due to the large scale spread of Middle Neolithic European farmer ancestry across the entire Pontic-Caspian steppe, probably from its western half, resulting in the formation of the Steppe_MLBA genotype, exemplified by the Sintashta and Srubnaya people. 
- Ancient DNA suggests that Bronze Age steppe groups were highly patrilocal, and if so, it's likely that most of the mixture on the steppe at this time was facilitated via female exogamy (i.e. foreign brides), which would explain the lack of typically Caucasian Y-haplogroups, such as J2, in Bronze Age steppe and derived ancient groups sampled to date, such as the Corded Ware people and eastern Bell Beakers.
He also notes that Steppe people were highly mobile and that the circumstances encouraged admixture of Steppe peoples. There are some key unstated points are key as well (my statements, not a quotation):
* Steppe men are overwhelmingly Y-DNA R1, while this is rare among Caucasian men of any time period. Actually, Yamnaya culture men are predominantly Y-DNA R1b in the case of the Yamnaya, although the ancient DNA of Steppe men further to the North and in the Corded Ware Culture (which also had a more northern orientation) overwhelmingly reveals Y-DNA R1a.  (In both cases, of high derived version of each haplogroup, not the most basal versions.)
* Yamnaya autosomal genetics can be decently approximated by blending ancient DNA from Eastern Hunter-Gatherers (60%) and Caucasian Hunter-Gatherers (40%). This is what makes it necessary to hypothesize an influx of foreign Caucasian brides. See, e.g., here (migration from the Steppe paper) and here (earlier Eurogenes post analyzing ancient DNA samples). Genetic evidence of Caucasian admixture in ancient DNA is absent on the steppe until the Eneolithic (i.e. the Copper Age).
* Early Neolithic Caucasian farmers appear to have been largely derived from Caucasian Hunter-Gatherers, in situ, rather than largely replacing existing hunter-gatherers in places where they expanded as first wave Neolithic people in Europe derived from Anatolian Neolithic people did.  (See also here).
* There is strong physical evidence of patrilocality and large numbers of wives who migrate to their husband's homes from considerable distances from the remains of central European Bell Beaker men who have significant steppe ancestry. Other physical anthropology studies of Bronze Age European women have reached similar conclusions.
There is also anthropological corroboration for this hypothesis (again, my observations and not a quotation):
* Much of the metallurgy technology package that will subsequently be spread across Europe by people with significant steppe ancestry was probably first developed in the Caucasus mountains area. 
* The source of the steppe farming and herding package is less obvious, with David Anthony making a fairly solid case from archaeology in The Horse, The Wheel and Language for a basically Balkan origin of farming and herding technologies on the steppe. In general, there is considerable confusion among historical linguists and pre-historians over why Proto-Indo-European seems to have so many horticulture specific  and maritime shared root words for a society often conceptualized as made up of herders. Hunter-gatherers tend to transition much more easily to a pastoralist lifestyle (i.e. herding) than to horticulture that requires a much greater lifestyle and worldview change. But, the Early European Farmer autosomal DNA does not show up in Steppe populations until the Middle Bronze Age, so it is hard to seem Balkan farmers playing an important demic role in the formation of the steppe genotype. 
* The Caucasus mountains is also one possible source of a religious theme of a fire cult (also here) that is visible in the Zoroastrian religion which was established by Indo-Iranians (although also possibly in BMAC temples in the Harappan trade network and there is some linguistic evidence to support the idea that they shared a language with the Harappans from substrate words in Indo-Iranian and Indo-Aryan languages), although the center of gravity of this cult seems further east and later in time to be a good fit. A possibly residual fire cult can also be found in the cult of Hephaestus in the Aegean (with parallels in both Indo-European and non-Indo-European deities elsewhere in the region), although Hephaestus may have pre-Mycenean Greek roots as this blacksmith god is closely associated with the island of Lemnos which was one of the last non-Indo-European language hold outs in the region which was spoken until the 6th century BCE. The God's deformity is characteristic of Bronze Age rather than Iron Age smiths, who were often poisoned by arsenic associated with tin needed to make Bronze. 
The link between Caucasian brides and the people of the Pontic-Caspian steppe which is pretty much the only credible source of the main expansion (at least) of the Indo-European languages, however, is complicated. 

Did Caucasian brides and their children come to speak their husband's steppe language?  Or, could Indo-European be a Caucasian origin language passed from mother to child on the steppe?

The Caucasian mountains are currently home to several families of non-Indo-European languages that appear in a variety of respects (e.g. elaborate grammar and uncommon phonemes) to relict languages from a very long time ago (probably back at least to the early Neolithic in the region) that have not been heavily influenced by language contact or first language learners in highly isolated mountain valleys. The evidence from ancient mtDNA tends to confirm population genetic continuity in the Caucasus, although the ancient Y-DNA evidence seems to show more change over time.

So, the former hypothesis, that brides and their children came to speak their husband's language, seems more likely and has some corroboration in the pattern observed in similar situations that are historically attested.

One possibility is that Southern steppe people were not originally Indo-Europeans and had a strongly Caucasian influenced language (possibly related to Minoan and Basque), but that northern steppe people were Indo-Europeans. The fact that early Iberian Bell Beaker culture people seem to largely lack steppe ancestry, even though non-Iberian Bell Beaker people have it to a great degree, however, complicates the story.

New ancient DNA to come from ancient Minoans (non-Indo-European pre-Greeks of Crete), Mycenaeans (the first Greek speaking people of the Aegean), Maykop culture people (a technological source culture at the foothills of the Caucasus mountains near the Black Sea coast), and Harappans (pre-Indo-Europeans of the Indus River Valley civilization) will help shed some light on the different possible hypotheses in the near future.

How To Rule Out The Extra Dimensions Of String Theory

A blog post by Sabine Hossenfelder at Backreaction reviews a new paper that discusses how the existence of more than four dimensions, even is accessible only to gravitons, as required by string theory (which needs ten or eleven dimensions), could be ruled out with the LIGO gravitational wave detector and two comparable independent gravitational wave detectors.

Current experiments place bounds on the size of any extra dimensions as follows:
The mass of these excitations is inversely proportional to the radius (in natural units). This means if the radius is small, one needs a lot of energy to create an excitation, and this explains why he haven’t yet noticed the additional dimensions. . . .
From the current lack of observation, one can then derive bounds on the size of the extra-dimension. These bounds depend on the number of extra-dimensions and on their intrinsic curvature. For the simplest case – the flat extra-dimensions used in the paper – the bounds range from a few micrometers (for two extra-dimensions) to a few inverse MeV for six extra dimensions (natural units again).
Basically, gravitational waves, even the ordinary ones we can detect with LIGO (as opposed to the excited ones that involve exited gravitons that have excitations in extra dimensions) behave differently in a world with extra dimensions (even compactified dimensions that only gravitons can enter), than they do in general relativity.

If extra dimensions exist, there are excited states of all particles, gravitons have additional polarizations, and they exhibit a kind of oscillation known as a "breathing mode" that does not exist in general relativity. 

Absolutely ruling out the possibility is a technically difficult feat, but placing profoundly more strict limits on their number and size is considerably more straight forward. Only a narrow sub-type of extra dimensions is particular hard to detect with this methodology. So, it would be fairly easy to limit any possible string theory to the kind with that narrow subtype of extra dimensions.

Saturday, May 20, 2017

Sometimes Simple Things Are Complicated

In quantum physics, some interactions that seem simple, like two photons that interact in a manner that ultimately produces two photons, are actually wickedly complex. This is because you have to consider every conceivable way consistent with the laws of quantum mechanics that you can get from the starting state to the end state.

In this simple scenario, called light by light scattering, that means considering the possibility that the two photons have paths that include all sorts of mesons (two quark particles) that are created and destroyed in intermediate steps in the interactions, either as "real" particles or "virtual" ones (called "off shell").

A recent paper tackling some of the deep complexities of this seemingly simple interaction by analyzing fifteen of the most important intermediate meson paths is here.

Wednesday, May 17, 2017

Quick Physics Hits

Another experiment favors lepton universality and casts doubt on data tending to show lepton universality violations.

The XENON-100 direct dark matter detection experiment again sees no dark matter and extends the exclusion range in WIMP parameter space.

The First Mass Extinction Was Probably Caused By Volcanos

There have been five mass extinctions since the divergent evolution of early animals 600 -450 million years ago. The cause of the third and fourth was volcanic activity, while an asteroid impact led to the fifth. But triggers of the first and second mass extinctions had, until now, been unknown. 
The first mass extinction occurred at the end of the Ordovician. This age is between the divergence of the Ordovician and land invasion of vascular land plant and animals. Animals in the Ordovician-Silurian comprised marine animals like corals, trilobites, sea scorpion, orthoceras, brachiopods, graptolite, crinoid and jawless fish. Approximately 80% of species disappeared at the end of the Ordovician.
From here.

The Ordovician spans 41.2 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya (per Wikipedia). The cause of the Devonian extinction event ca. 365 million years ago, which killed many tropical marine species is still not known.

Elevated mercury levels at the transition point measured in two locations suggest a volcanic trigger for the extinction, although it isn't clear why these volcanic eruptions took place at this time. The paper is:

David S. Jones, Anna M. Martini, David A. Fike, Kunio Kaiho. "A volcanic trigger for the Late Ordovician mass extinction? Mercury data from south China and Laurentia." Geology (May 2017) G38940.1

Movius Line Discredited By Acheulian Artifacts Found In Asia

[T]he Movius Line (Movius, 1948) over which no Acheulian artefacts were argued to occur in East Asia is no longer an appropriate concept for the Early Paleolithic of East and Southeast Asia and should be disregarded[.]
From here.

In 1948, it appeared from the archaeological record that Homo Erectus in Asia was completely technologically static. Advances in the design and construction of stone tools, called Acheulian technology, were found elsewhere, but not in Asia to the east of the "Movius Line".

But, new well dated Asian finds of Acheulian artifacts tell a different story. As the body text of the new paper explains:
Acheulian technology is characterized by bifacially and unifacially shaped tool types, such as handaxes, cleavers, picks and other large cutting tools (LCTs) (Isaac, 1969; Bar-Yosef and Goren-Inbar, 1993; Goren-Inbar et al., 2000; Semaw et al., 2009; Lepre et al., 2011; Beyene et al., 2013 ; Diez-Martín et al., 2015). Its appearance represents a technological advance over the preceding Oldowan technology, and is associated with innovative hominin cognitive and adaptive abilities (Goren-Inbar, 2011 ; Stout, 2011). Current thinking is that Acheulian technology originated in East Africa (possibly West Turkana, Kenya) at least 1.76 million years ago (Ma) (Lepre et al., 2011), that it became distributed somewhat widely across Africa (e.g., Vaal River Valley and Gona) at ∼1.6 Ma (Gibbon et al., 2009 ; Semaw et al., 2009), and then spread to the Levant at ∼1.4 Ma (Bar-Yosef and Goren-Inbar, 1993), South Asia at 1.5–1.1 Ma (Pappu et al., 2011), and Europe at 1.0–0.9 Ma (Scott and Gibert, 2009 ; Vallverdú et al., 2014) (Fig. 1). The 0.8–0.9 Ma Acheulian stone stools from South and central China (Hou et al., 2000 ; de Lumley and Li, 2008) (Fig. 1) suggest that Acheulian technology arose in China at least during the terminal Early Pleistocene. However, there are only a few sites with in situ Acheulian artefacts from North China with ages ranging from the late Mid-Pleistocene to the Late Pleistocene ( Wang et al., 2014 ; Yang et al., 2014) (Fig. 1). Thus, it remains enigmatic as to how early Acheulian technology can be traced back in North China, compared with its Early Pleistocene occurrence in South and central China. 
Sanmenxia Basin (also Sanmen area), which lies on the southeastern Loess Plateau, is a rich source of stone artefacts and is an important area for understanding the early human occupation of North China (Jia et al., 1961; Huang, 1964; Jia, 1985 ; Li, 1990). The first Early Pleistocene Paleolithic site in China, that is the Xihoudu site dated at 1.4–1.27 Ma (Zhu et al., 2003 ; Kong et al., 2013), was found in northwestern Sanmenxia Basin (Fig. 1) in 1961–1962 (Jia, 1985). In 1963, 128 stone artefacts were found from 6 localities in eastern Sanmenxia Basin (Huang, 1964). Among the 128 artefacts, 94 were from the Shuigou and Huixinggou sites (Huang, 1964). At that time the chronology of the Chinese loess-paleosol sequence was not yet established; a tentative Mid-Pleistocene age was suggested for the lithic assemblage based on lithostratigraphic arguments (Huang, 1964). Furthermore, when these artefacts were discovered, consensus was that Acheulian handaxes and cleavers were lacking in East Asia during the period when they flourished in Africa and western Eurasia (Movius, 1948). Therefore, the handaxe and cleavers from the Shuigou and Huixinggou sites (Fig. 2) were not recognized and reported as Acheulian artefacts; instead, they were considered to represent different kinds of choppers that are indicative of a chopper-chopping tool industry (Huang, 1964; Huang, 1987; Huang, 1993 ; Lin, 1992).
This matters because it gives us a detailed assessment in time and space of the range of Homo Erectus and of the spread of a new kind of lithic tool technology by this archaic hominin species. It also suggests that Asian Homo Erectus was more plastic mentally than early estimates supported by the now disprove Movius Line theory suggested. The paper is: 

Xingwen Li, et al. "Early Pleistocene occurrence of Acheulian technology in North China" 156 Quaternary Science Reviews 12-22 (2017).

Another PLOS paper along the same lines is also noted at Linear Population Model.

The Movius Line was previously discussed at this blog in 2011.

Riding Cows

Both Spain and Crete have historic "cow" cultures and, of course, cows are sacred in India.

I don't normally post videos from YouTube at this blog, but a video of a New Zealand girl riding a cow like a horse suggests that maybe we underestimate the ways the cows can be utilized.

Tuesday, May 16, 2017

Brain Size Increased Before Brain Region Specialization

The study of 58 species of songbirds also found that once a species evolved a larger brain, brain regions that control the beak and mouth, and the area for song, developed additional complex neural networks. . . . 
The findings suggest that this principle may also help explain human evolution; we may have first evolved larger brains, which then allowed for adaptations that enhanced brain regions that control specific abilities, such as language.
From here.

From a practical perspective, this makes the task of a would be trans-humanist attempting nootropic enhancements of the human genome straightforward. Select for a larger brain size and see what happens.

The paper is:

Jordan M. Moore, Timothy J. DeVoogd. "Concerted and mosaic evolution of functional modules in songbird brains." 284 Proceedings of the Royal Society B: Biological Sciences 1854 (May 10, 2007): 20170469.

Domesticated Crops Have Larger Seeds

Domesticated crops have larger seeds than the comparable wild type, even though there is good reason to doubt that early proto-farmers intended this result.

The paper is:

Thomas A. Kluyver, et al., "Unconscious selection drove seed enlargement in vegetable crops." Evolution Letters (2017).

Recent Experimental Measurements Of Standard Model Constants

W Boson Mass At The LHC (ATLAS) and Tevatron (CDF)
The result of the CDF analysis is MW = 80 387±12(stat.)±15(syst.) MeV; the result of the ATLAS analysis is MW = 80 370 ± 7(stat.) ± 11(exp.syst.) ± 14(mod.syst.) MeV. The total uncertainty is 19 MeV in both analyses.
From here.

My comments: The lighter ATLAS result is closer to a result expected from a global electroweak fit. The Tevatron based results will never get better because that experiment has concluded. The LHC based results will almost surely get better before the experiment concludes, if for no other reason, because the statistical error will get a bit smaller over time and because independent results from ATLAS and CMS can be combined reducing a little systemic error as well.

Heavy Quark Masses And The Strong Coupling Constant From HERA

New results on the measurements of the hadronic final state in neutral-current deep-inelastic scattering at HERA are presented. A combination of reduced charm and beauty cross sections is presented and the masses of the heavy quarks are determined to mc=1290(+7853)MeV and mb=4049(+138118)MeV. The measurement of the production of prompt photons accompanied by a jet provides a precise test of QCD predictions. Measurements of jet production cross sections are presented and compared for the first time to next-to-next-to-leading order predictions (NNLO). The strong coupling constant is determined from inclusive jet and dijet production cross sections using NNLO predictions to αs(mZ)=0.1157(6)exp(+3126)th.

My comments: The charm quark mass is a bit high, (also here and here) and bottom quark mass is a bit on the low side, as is the strong force coupling constant. But, all of the measurements have significant margins of error, so the differences aren't very meaningful.

CKM Matrix Elements Involving Bottom Quarks At Belle II

Semileptonic B meson decays involving low-mass charged leptons e or μ are expected to be free of non-Standard Model contributions and therefore play a critical role in determinations of |Vub|and |Vcb|. Of all the CKM matrix parameters, |Vub| is the least precisely measured and in most need of additional studies in order to better constrain the apex of the Unitarity Triangle. We focus on exclusive reconstruction of charmless semileptonic B meson decay Bπν, and present prospects and estimates for measuring |Vub| at Belle II with the full planned dataset of 50 ab1 of integrated luminosity.

My comments: These two element are hard to measure because Vtb = 0.99914 +/- 0.00005 is dominant, and Vub = 0.00355 ± 0.00015, in particular, is very small. The square of Vub which represents the probability is 1.26 per 100,000. The paper discusses prospects for improvements in accuracy in future measurements of this CKM matrix elements and does not actually contain any measurements.

UPDATE May 18, 2017: A survey of recent measurements of four CKM matrix elements is found here. END UPDATE.

Theoretically Expected Higgs Boson Diphoton Decays

Physicists have replicated, in a more general matter than a previous result, the conclusion that many of the terms that go into calculating the likelihood that a Higgs boson will experience a diphoton decay cancel out. In particular, they show "the cancellation of all terms among the Feynman diagrams which are to be integrated to give divergences higher than logarithmic." This conclusion which requires 30 dense pages of calculations implies that calculating the likelihood of this decay is much easier than would be naively expected.